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Non-volatile Multi-level Switching in Artificial Synaptic Transistors Based on Epitaxial LiCoO2 Thin Films



Heshan Yu, Megan E. Holtz, Yunhui Gong, Justin Pearson, Yaoyu Ren, Andrew Herzing, Xiaohang Zhang, Ichiro Takeuchi


Li-ion synaptic transistors offer non-volatile multi-level switching through Li-ion exchange between channel and electrolyte, and thus are widely regarded as promising candidates for the neuromorphic computing. However, a relatively low switching speed in devices fabricated on polycrystalline films still greatly limits the application scope of these devices. To optimize the device performance, improving the crystallinity of the channels is a direction being actively pursued. In this study, we systematically investigate of the multi-switching operation in the Li-ion synaptic devices fabricated on epitaxial Li1-xCoO2 (LCO) thin films with different orientations. Programming these devices with a series of presynaptic pulses, non- volatile potentiation and depression states are established and confirmed to be stable for a period at least three times of the pulse duration. By reducing the thickness of the LCO channel, the signal-to-noise ratio of the non-volatile switching can be substantially improved. Changes in the potentiation and depression states are found to significantly depend on the lattice orientation of the LCO channel, suggesting that an anisotropic Li-ion diffusion rate in highly-crystallized LCO films plays an important role in the device performance.
Physical Review Materials


Neuromorphic computing, electronic device, battery, thin film, pulsed laser deposition, scanning transmission electron microscopy


Yu, H. , Holtz, M. , Gong, Y. , Pearson, J. , Ren, Y. , Herzing, A. , Zhang, X. and Takeuchi, I. (2021), Non-volatile Multi-level Switching in Artificial Synaptic Transistors Based on Epitaxial LiCoO2 Thin Films, Physical Review Materials, [online], (Accessed April 24, 2024)
Created October 26, 2021, Updated October 28, 2022